<?php
//=======================================================================
// File:	PDF417_ERROR.INC
// Description:	Calculate the Reed-Solomon error corection
// Created: 	2004-03-01
// Ver:		$Id: pdf417_error.inc.php,v 1.1 2007-09-10 18:40:26 michis Exp $
//
// License:	This code is released under QPL 1.0
// Copyright (C) 2004 Johan Persson
//========================================================================


// This class currently only handles the calculation of Reed-Solomon
// code words. It does not handle decoding and error correction using
// esisting data and code words. 
class ReedSolomon {

// Reed-Solomon Gnereator Polynomial Coefficients

    private $iPolCoeff = array(

/* Level 0 */
    array( 27, 917 ),

/*  Level 1*/ 
    array(522, 568, 723, 809 ), 

/*  Level 2 */
    array(237, 308, 436, 284, 646, 653, 428, 379 ),

/*  Level 3 */
    array(274, 562, 232, 755, 599, 524, 801, 132, 295, 116, 442, 428, 295,  42, 176,  65 ),

/*  Level 4 */
    array(361, 575, 922, 525, 176, 586, 640, 321, 536, 742, 677, 742, 687, 284, 193, 517, 
	  273, 494, 263, 147, 593, 800, 571, 320, 803, 133, 231, 390, 685, 330, 63, 410 ),

/*  Level 5 */
    array(539, 422, 6, 93, 862, 771, 453, 106, 610, 287, 107, 505, 733, 877, 381, 612, 
	  723, 476, 462, 172, 430, 609, 858, 822, 543, 376, 511, 400, 672, 762, 283, 184, 
	  440, 35, 519, 31, 460, 594, 225, 535, 517, 352, 605, 158, 651, 201, 488, 502, 
	  648, 733, 717, 83, 404, 97, 280, 771, 840, 629, 4, 381, 843, 623, 264, 543 ),

/*  Level 6 */
    array(521, 310, 864, 547, 858, 580, 296, 379,  53, 779, 897, 444, 400, 925, 749, 415, 
	  822,  93, 217, 208, 928, 244, 583, 620, 246, 148, 447, 631, 292, 908, 490, 704, 
	  516, 258, 457, 907, 594, 723, 674, 292, 272,  96, 684, 432, 686, 606, 860, 569, 
	  193, 219, 129, 186, 236, 287, 192, 775, 278, 173,  40, 379, 712, 463, 646, 776, 
	  171, 491, 297, 763, 156, 732,  95, 270, 447,  90, 507,  48, 228, 821, 808, 898, 
	  784, 663, 627, 378, 382, 262, 380, 602, 754, 336,  89, 614,  87, 432, 670, 616, 
	  157, 374, 242, 726, 600, 269, 375, 898, 845, 454, 354, 130, 814, 587, 804,  34, 
	  211, 330, 539, 297, 827, 865,  37, 517, 834, 315, 550,  86, 801,   4, 108, 539),

/*  Level 7 */
    array(524, 894, 75, 766, 882, 857, 74, 204, 82, 586, 708, 250, 905, 786, 138, 720, 
	  858, 194, 311, 913, 275, 190, 375, 850, 438, 733, 194, 280, 201, 280, 828, 757, 
	  710, 814, 919, 89, 68, 569, 11, 204, 796, 605, 540, 913, 801, 700, 799, 137, 
	  439, 418, 592, 668, 353, 859, 370, 694, 325, 240, 216, 257, 284, 549, 209, 884, 
	  315, 70, 329, 793, 490, 274, 877, 162, 749, 812, 684, 461, 334, 376, 849, 521, 
	  307, 291, 803, 712, 19, 358, 399, 908, 103, 511, 51,  8, 517, 225, 289, 470, 
	  637, 731, 66, 255, 917, 269, 463, 830, 730, 433, 848, 585, 136, 538, 906, 90, 
	  2, 290, 743, 199, 655, 903, 329, 49, 802, 580, 355, 588, 188, 462, 10, 134, 
	  628, 320, 479, 130, 739, 71, 263, 318, 374, 601, 192, 605, 142, 673, 687, 234, 
	  722, 384, 177, 752, 607, 640, 455, 193, 689, 707, 805, 641, 48, 60, 732, 621, 
	  895, 544, 261, 852, 655, 309, 697, 755, 756, 60, 231, 773, 434, 421, 726, 528, 
	  503, 118, 49, 795, 32, 144, 500, 238, 836, 394, 280, 566, 319,  9, 647, 550, 
	  73, 914, 342, 126, 32, 681, 331, 792, 620, 60, 609, 441, 180, 791, 893, 754, 
	  605, 383, 228, 749, 760, 213, 54, 297, 134, 54, 834, 299, 922, 191, 910, 532, 
	  609, 829, 189, 20, 167, 29, 872, 449, 83, 402, 41, 656, 505, 579, 481, 173, 
	  404, 251, 688, 95, 497, 555, 642, 543, 307, 159, 924, 558, 648, 55, 497, 10),

/*  Level 8 */
    array(352, 77, 373, 504, 35, 599, 428, 207, 409, 574, 118, 498, 285, 380, 350, 492, 
	  197, 265, 920, 155, 914, 299, 229, 643, 294, 871, 306, 88, 87, 193, 352, 781, 
	  846, 75, 327, 520, 435, 543, 203, 666, 249, 346, 781, 621, 640, 268, 794, 534, 
	  539, 781, 408, 390, 644, 102, 476, 499, 290, 632, 545, 37, 858, 916, 552, 41, 
	  542, 289, 122, 272, 383, 800, 485, 98, 752, 472, 761, 107, 784, 860, 658, 741, 
	  290, 204, 681, 407, 855, 85, 99, 62, 482, 180, 20, 297, 451, 593, 913, 142, 
	  808, 684, 287, 536, 561, 76, 653, 899, 729, 567, 744, 390, 513, 192, 516, 258, 
	  240, 518, 794, 395, 768, 848, 51, 610, 384, 168, 190, 826, 328, 596, 786, 303, 
	  570, 381, 415, 641, 156, 237, 151, 429, 531, 207, 676, 710, 89, 168, 304, 402, 
	  40, 708, 575, 162, 864, 229, 65, 861, 841, 512, 164, 477, 221, 92, 358, 785, 
	  288, 357, 850, 836, 827, 736, 707, 94, 8, 494, 114, 521, 2, 499, 851, 543, 
	  152, 729, 771, 95, 248, 361, 578, 323, 856, 797, 289, 51, 684, 466, 533, 820, 
	  669, 45, 902, 452, 167, 342, 244, 173, 35, 463, 651, 51, 699, 591, 452, 578, 
	  37, 124, 298, 332, 552, 43, 427, 119, 662, 777, 475, 850, 764, 364, 578, 911, 
	  283, 711, 472, 420, 245, 288, 594, 394, 511, 327, 589, 777, 699, 688, 43, 408, 
	  842, 383, 721, 521, 560, 644, 714, 559, 62, 145, 873, 663, 713, 159, 672, 729, 
	  624, 59, 193, 417, 158, 209, 563, 564, 343, 693, 109, 608, 563, 365, 181, 772, 
	  677, 310, 248, 353, 708, 410, 579, 870, 617, 841, 632, 860, 289, 536, 35, 777, 
	  618, 586, 424, 833, 77, 597, 346, 269, 757, 632, 695, 751, 331, 247, 184, 45, 
	  787, 680, 18, 66, 407, 369, 54, 492, 228, 613, 830, 922, 437, 519, 644, 905, 
	  789, 420, 305, 441, 207, 300, 892, 827, 141, 537, 381, 662, 513, 56, 252, 341, 
	  242, 797, 838, 837, 720, 224, 307, 631, 61, 87, 560, 310, 756, 665, 397, 808, 
	  851, 309, 473, 795, 378, 31, 647, 915, 459, 806, 590, 731, 425, 216, 548, 249, 
	  321, 881, 699, 535, 673, 782, 210, 815, 905, 303, 843, 922, 281, 73, 469, 791, 
	  660, 162, 498, 308, 155, 422, 907, 817, 187, 62, 16, 425, 535, 336, 286, 437, 
	  375, 273, 610, 296, 183, 923, 116, 667, 751, 353, 62, 366, 691, 379, 687, 842, 
	  37, 357, 720, 742, 330, 5, 39, 923, 311, 424, 242, 749, 321, 54, 669, 316, 
	  342, 299, 534, 105, 667, 488, 640, 672, 576, 540, 316, 486, 721, 610, 46, 656, 
	  447, 171, 616, 464, 190, 531, 297, 321, 762, 752, 533, 175, 134, 14, 381, 433, 
	  717, 45, 111, 20, 596, 284, 736, 138, 646, 411, 877, 669, 141, 919, 45, 780, 
	  407, 164, 332, 899, 165, 726, 600, 325, 498, 655, 357, 752, 768, 223, 849, 647, 
	  63, 310, 863, 251, 366, 304, 282, 738, 675, 410, 389, 244, 31, 121, 303, 263)
    );

    // Checksums for the Reed-Solomon Tables above to guarantee file integrity
    private $iChkSum = array(array(701,63),array(40,888), array(632,49),
			 array(141,603),array(818,93),array(413,413),
			 array(80,232),array(399,117), array(151,444));

    function ReedSolomon() {
        // Check integrity of code and code tables
        $n = count($this->iPolCoeff);
        for($i=0; $i < $n; ++$i) {
            $coeff = $this->iPolCoeff[$i];
            $cw = $this->GetCodewords($coeff,0);
	    /*
	    echo "array( ";
	    for( $j=0; $j < count($cw); ++$j ) {
		echo $cw[$j].",";
	    }
	    echo " ),\n";
	    */
            if( $this->iChkSum[$i] != $cw ) {
                JpGraphError::RaiseL(25013); //'Coefficient tables corrupted');
            }
        }
    }

    function GetNumCodewords($aLevel=1) {
	return 1 << ($aLevel+1);
    }

    function GetCodewords($aData,$aLevel=1) {
	$n = count($aData);
	if( $n == 0 ) 
	    JpGraphError::RaiseL(25014); //'No data to calculate codewords on.');
	$k = 1 << ($aLevel+1);	
	$ck=array();
	$m = 929;
	for($i=0; $i < $k; ++$i ) $ck[$i] = 0;
	$t1 = $t2 = 0;
	for( $i=0; $i < $n; ++$i ) {
	    $t1 = ($aData[$i]+$ck[$k-1]) % $m;
	    for( $j=$k-1; $j > 0; --$j ) {
		$t2 = ($t1 * $this->iPolCoeff[$aLevel][$j]) % $m;
		$ck[$j] = ($ck[$j-1]+($m-$t2)) % $m;
	    }
	    $t2 = ($t1 * $this->iPolCoeff[$aLevel][0]) % $m;
	    $ck[0] = ($m-$t2) % $m;
	}
	for( $i=0; $i < $k; ++$i ) {
	    if( $ck[$i] > 0 ) $ck[$i] = $m - $ck[$i];
	}
	return array_reverse($ck);
    }
}

?>
